Reactor Disaster Poses Health Risks

Japanese health authorities have confirmed that at least 22 people have been exposed to radiation following the hydrogen explosion at the Fukushima Daiichi Nuclear Power Station's No. 1 reactor building early Saturday morning.

Up to 160 more are thought to have been exposed while waiting for evacuation in the nearby town of Futabe, according to Ryo Miyake, a spokesman from Japan's nuclear agency.

A cooling system malfunction at the plant's No. 3 reactor last night could lead to a similar explosion, but Yukio Edano, the nation's Chief Cabinet Secretary, said, "If there is an explosion, however, there would be no significant impact on human health," according to the Associated Press.

Workers wearing masks and protective clothing are using handheld scanners to measure radiation after more than 300,000 were urged to flee the 450-square mile zone.

Officials have set up evacuation centers bordering the zone and are working to establish decontamination facilities.

Depending on the level of contamination, evacuees are being advised to dispose of clothing and shower.

"They're doing the same thing we would be doing," said ABC News chief medical editor Richard Besser, MD. "They'll be monitoring them to see if they have radiation on them. They can decontaminate them."

Potassium iodide is also being distributed to guard against thyroid cancer.

"You can't prevent all the consequences, but you can prevent thyroid cancer," Besser said.

"One of the things after Chernobyl, you saw massive numbers of cancers in children. The radioactive iodine got into the grass, the cows ate the grass, it got into the milk," Besser said. "If there is a big fallout, they'll tell people not to drink milk or eat food from that area."

Children and pregnant women are most at risk, Besser said.

Although the steel container protecting the plant's No.1 reactor was not damaged in the explosion, radiation levels near the plant rose to roughly twice that which constitutes an emergency situation, according to Japanese officials. This prompted a doubling of the evacuation radius from the initial six miles.

Radiation levels outside the plant rose again after the malfunction in the No. 3 reactor Saturday night, but soon began to fall, according to Edano.

The explosion in the No. 1 reactor occurred when a build-up of steam was released in an effort to safely decrease pressure. A similar controlled release is planned for No. 3.

"We don't call this situation meltdown," government spokesman, Nori Shikata told This Week anchor Christiane Amanpour Sunday morning. "This is a regulated controlled situation. The release of minute radioactive material is based on our efforts to take precautionary methods."

"Whether or not there will be further leaks, the people will be away from danger," Besser said.

Jacky Williams, director and core leader of the Center for Biophysical Assessment and Risk Management Following Irradiation at the University of Rochester Medical Center, called the 12-mile evacuation radius an "extremely conservative safety zone to protect against fallout."

The radiation dose following the Hiroshima and Nagasaki bombings was cut in half every 200 meters from ground zero, Williams said.

But the fallout from a Fukushima could vary greatly depending on the nature of any leak -- whether it's through an explosion of the core, as in Chernobyl, or a slow, controlled release of pressure -- building gases -- and the wind.

"Members of the public are not in imminent danger at a distance of 20 kilometers (12 miles), so long as they are not downwind," Williams said.

The plume from the Chernobyl explosion drifted over large parts of Europe and the Soviet Union, prompting the evacuation of more than 300,000 people.

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